K., once you establish there is no reason to worry as far as safety or bullying is concerned this may be a defining moment in the dynamics of the house between your son and responding to authority. he may just be exhibiting rebellion because he'd rather be somewhere else instead of there, or someone made fun of the fact that he attends the classes, he may prefer to be at home, who knows? you have to decide whether are you willing to give the reins of power to your son at 7 years old~ this may not be not about the classes, per ce, but about you being able or unable to control your 7-year old child from now on. (and the next one, if it works for your oldest, because the younger one will learn from him how to manipulate you).
i never bribed my kids. i also don't reward them for behaviour that is expected of them. what you're experiencing right now could very well be a power struggle and you should decide right now, because if you lose...you will be fighting a difference battle every day/week/month.
my children are now 19, 18 and 12 and although we have had our disagreements the word or their father or mother was never up for grabs in terms of going over our authority. nip it in the bud so you don't go through this the next 14 years.
don't miss the bigger picture in this and good luck!
as i read the other responses i find it unsettleting to think that K. is being told to rethink the religion classes or to imply she is being unreasonable or hypocritical. (kids learn by example...indeed) she is the mother of this child and it is her right and her duty to teach him in whatever way she desires, whatever religious or tradition she wishes. kids don't get to run their lives at this age or make decisions that will follow them for the rest of their lives. kids are not adults in small size. they are children who don't understand serious ramifications of decisions given to them. it does explain why i see so many kids who yell at their mothers in public, cause a scene and the parents end up asking "what went wrong?" when they have lost all control over their kids at an early age. K., are the classes important to you? to your husband? is it your tradition as a family? take your child! a kid this age should decide what he wants to wear, not to whether or not go to religion.
there's a great proverb: "the wise son brings honor to his father, a foolish son is the shame of his mother".
Do what is important to you, K.. when he is a man, and the teenage years are over...he will be grateful that you taught him to do what is expected of him. so will his boss, his wife, and his teachers.